The present invention relates to an improved display system to provide information to an observer.
Display systems are commonly utilized in aircraft to provide information to a pilot of the aircraft. When the aircraft is parked on the ground, the aircraft may be at a relatively low or relatively high temperature. Immediately prior to flight, the temperature of the interior of the aircraft is quickly changed to be comfortable for an occupant of the aircraft. This results in the components of the display system in the aircraft being subjected to a relatively wide range of temperatures within a short period of time.
In order to determine whether or not a display system can withstand thermal stresses resulting from repeated exposure to this wide range of temperatures, the display system may be subjected to a temperature test. The temperature test includes a plurality of test cycles during which the temperature of the display system is changed in a range which varies from -55.degree. C. to +85.degree. C. During each test cycle, the display system is electrically energized at various temperatures.
If a display system can withstand 19 cycles of the temperature test without failure, the display system may be judged to be satisfactory for use in a specific aircraft. A known display system includes six light emitting diodes which are disposed on a ceramic support. When a plurality of these display systems were subjected to the temperature test, most of the display systems failed after they had been subjected to between five and sixteen cycles of the temperature test. It is interesting to note that 350 cycles of the temperature test may be considered to exceed the thermal stresses encountered during the operating life of a specific aircraft.